is_nan
(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
is_nan — Finds whether a value is not a number
Description
$num
): bool
Checks whether num
is 'not a number',
like the result of acos(1.01)
.
Parameters
-
num
-
The value to check
Return Values
Returns true
if num
is 'not a number',
else false
.
Examples
Example #1 is_nan() example
<?php
// Invalid calculation, will return a
// NaN value
$nan = acos(8);
var_dump($nan, is_nan($nan));
?>
The above example will output:
float(NAN) bool(true)
See Also
- is_finite() - Finds whether a value is a legal finite number
- is_infinite() - Finds whether a value is infinite